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3D DIRECT • December 11, 2000

The Artist's Canvas

No Clean and Crisp Edges, Please!

by Eni Oken

Since the beginning of 3D computer graphics, artists and viewers alike have complained about the artificiality of computer-produced images. Although few people are able to put their finger on it, one of the main reasons for that artificial look is the lack of natural randomness around the edges of surfaces.

Observe two identical 3D models (which were recently used for a Cult3D tutorial on 3Dgate.com)—the first one does not have any textures applied, and the edges look sharp and clean. The second one has specific custom-made texture work applied to it, and looks more natural, even though the theme of the design is whimsical and cartoonish.

Figure 1: Two identical models show the difference when specific texture work is made to disguise the crisp and clean edges. Image courtesy Eni Oken, Copyright 2000 Eni Oken.

Look around you—nature is NOT crisp and clean. Even in objects that are man-made, there will always be little edges of dirt, dents, marks, and unevenness.

Texture work—the main tool

The most important tool of the 3D artist that can help disguises the crisp and clean edges of a model is texture work. By creating carefully made, custom textures for each surface, the edges can be disguised easily. Figure 2 shows the textures that were used for the main body of the object shown in Figure 1.

Figure 2: Notice how each side of the model was custom-made. Even the left side is different than the right side. Image courtesy Eni Oken, Copyright 2000 Eni Oken.

These custom-made textures not only reflect the shape of the model that will receive the texture, but also enhance and mark the perimeter of each surface. Each surface of the model received its own decal, specially made to order. Even the right side is different than the left side, although they have essentially the same basic format.

In order to prove that the work around the perimeter of the texture is really making a substantial difference, the model was rendered again. This time a simple green texture was applied to the texture, almost identical to the one used for the custom-made textures, except it contained no work around the edges. See Figure 3. Notice how immediately the crisp, clean edges appear again in Figure 3, removing part of the natural aspects of the model.

Figure 3: To prove that working around the edges of a texture really makes a difference, take a look at this version of the model with no custom-made work. Image courtesy Eni Oken, Copyright 2000 Eni Oken.

Edge-work: when to apply it?

The conclusion is that edge-work can greatly amplify the beauty and natural look of a model. But when should it be used?

Figure 4: Even if the subject does not call for realism, the use of edge-work can greatly enhance a piece of texture. Image courtesy Eni Oken, Copyright 2000 Eni Oken.

To answer that question, we need to analyze what surrounds us in the real world. If you look carefully, you'll notice that dust and grime gather on the objects around you. These observations can be valuable when determining when an edge-work of dust or dirt should be used, because, as you know, dirt and grime naturally gather more heavily in edges and corners. Most of the time, dirt and grime gather heavily in three situations:

  1. When one surface encounters another one of the same material at a 90 degree or tighter angle. For example, where two walls meet;
  2. When two surfaces meet on almost the same plane, but with a groove or cut between them. For example, between the wood boards on a picnic table;
  3. When one surface encounters another one of a DIFFERENT material—usually materials do not mesh well together and form dust. For example, a glass door with a metal door frame will allow dust to collect around the door jam.

There may be other situations where dust and grime gather, but following these rules will help you create 3D images that look more natural.

Even if the project being worked on does not require photographic realism, edge-work applied to the texture work can always improve the quality of the project. Figure 4 shows a whimsical door texture that has two obviously different types of materials (one is green wood and the other one… orange peel?). This falls into category 3 described above, that is, two different materials meet. The arrows show where the edge between materials was enhanced with a rather fake wide green border and some ornamental purple designs.

Notice also the existence of dark shadows applied to each division line. That enhances further each texture and edge treatment.

Edge-work style: more or less ornate?

And what about projects that require an industrial, very fabricated look? Even with models of a mechanical nature, the use of edge-work can improve the quality of the texture. Naturally, the style of the edge-work will be more rigid and contain more straight lines, but there is plenty of room for working with grunge, wear, and tear. Figure 5 shows an example of a texture image that contains a lot of edge-work: notice the white, irregular areas simulating wear and tear. Dents and irregularities are also present.

Figure 5: Mechanical themes, although using straighter lines, can also benefit from edge-work. Image courtesy Dan Oken.

But it is in whimsical, artistic, and historic themes that edge-work and ornate borders can be explored to their full potential. Figure 6 shows an elaborate piece of texture where there are so many examples of edge-work that it seems as if the entire piece is made of borders and ornamental trims.

Figure 6: Historical and artistic themes allow room for elaborate border and trim work. Image courtesy Eni Oken, Copyright 2000 Eni Oken.

And finally, in order to create good and appropriate work around the edges of a texture, it is also necessary to ask yourself:

  1. How much dirt, wear, and tear does this surface and edge-work need?

    Obviously it depends on the nature of the project, but most projects accept dirt, wear, and tear well. Especially games. Do not be afraid of applying a bit of dirt on to cartoonish themes, they usually work well in any situation.

  2. How elaborate can the trim and edge-work be in the traditional, ornamental sense?

    Even when the theme of the project requires a cleaner and starker look, do not discard a bit of ornament. Instead of using curly-cues, you can use rivets and mechanical objects to produce ornamentation.

  3. What color should I make the edge-work?

    If the main texture area that is being enhanced is quite dark, then consider making an edge that is lighter, so that the contrast will appear and mark the edge well. Remember that it is not always dust gathering that forms borders and edge markings—wear and tear can peel off the paint or material of a surface, revealing the white underneath. If the theme of the project allows a more colorful edge-work, then consider using a contrasting or complementary color.


Creating custom-made textures will always make a difference and make your models stand out. Enhancing the edges is just one way to make custom-texture work look good. Observing your surroundings to see how this is translated in the real world will greatly improve your understanding of this tool.

Eni Oken is a Brazilian freelance 3D artist based in Los Angeles. As an architect with 13 years of experience in computer graphics, she has participated in the creation of 3D art for numerous interactive projects and has won several awards for her work. You can reach Eni at: http://www.oken3d.com